I have a production server running BES SP3 HF1 with 400 users on Domino 6.5.3. I am setting up a second server to be a hot spare. I would like to go ahead and load SP5 to this server. Will there be any issues moving users to this server with SP5 from one with SP3 HF1? If I see no issues I will then upgrade the other to SP5.

I would suggeest loading SP5 to your current server and seeing how that goes and if you see / incurr any errors. Once you have completed that, then go ahead and load SP5 to your spare server and migrate the user's if necessary...

Usually, I would say the answer to your question is that there isnt a problem but rather be safe than sorry--

This issue has progressed further. ServerA is 4.0.3.11 while I just received the software and SRP for serverB and it is 4.1. Should I upgrade ServerA to 4.1 before loading ServerB (they will share the same besmgmt db on ServerC)

My safest route would be to get your servers up to the exact version for both (Pre 4.1), see how it runs and then plan on how you want to upgrade to 4.1 --when you want to upgrade to 4.1, you will have serious downtime when the DB and the State DB's have to be upgraded to accomodate for 4.1

If you are already on SP5, you'd better to be on SP 5 Hot Fix#2... there is 2 show stopper SDRs - if a non-standard message header or a large MIME message body is sent from BB.. server stopped responding. Check out release note:Livelink - Redirection

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